Aftermarket engine upgrade oﬀers additional power

Looking for a little more power to shorten that already awe-inspiring takeoﬀ roll? An AirCam owner recently completed the addition of an aftermarket engine cylinder and piston kit, and the results are impressive. The “big bore kit,” as it’s referred to increases the bore of the cylinders and pistons oﬀering a gain of an estimated 10-12 horsepower.

The upgrade was performed on the right engine ﬁrst, leaving the left engine as a fair basis for comparison in single engine performance at gross weight. The airplane weighed in at 1061 lbs empty, gross weight 1680 lbs. Flying at Sebring with a density altitude of 1700, we were immediately impressed by an improvement of 150 ft/min in single engine performance. The standard Rotax 912ULS engine averaged a single engine climb rate of 240 ft/min at gross weight, while the aftermarket upgrade averaged a single engine climb rate of 390 ft/min. The increase in power was noticeable right from the start, even requiring pitch adjustments to the prop to prevent an overspeed.

Lately I’ve been weighing in at 195 lbs. Later in the same week with both engines retroﬁtted with the aftermarket kit, I ﬂew solo with 3/4 tanks of fuel and was oﬀ the ground in 80 ft. Climbing from 500 ft. on a 2700 ft. density altitude day was just as impressive… 2000 ft/min! With a passenger and loaded at gross, takeoﬀs were nearly as remarkably short, and we averaged a 1600 ft/min climb.

It’s worth noting that we don’t know how the aftermarket engine upgrade will aﬀect engine life or oil consumption, but its safe to assume a decrease in TBO and and increase in oil consumption. If you’ve got a new set of engines, be aware that the retroﬁt is not aﬃliated with or approved by Rotax.